1. Field of the Invention
This invention relates to a dual propeller outboard assembly, to be used on marine vessels so as to maximize the propulsion rate possible with a single motor, thereby increasing the speed capability of the vessel without increasing the rate of fuel consumption.
2. Description of the Prior Art
Outboard motors are a common drive mechanism utilized in many marine vessels. Unfortunately, as with most motors, they consume large quantities of fuel and have limited drive capability. For this reason, many large vessels often utilize two outboard motors, which while doubling the drive power also doubles the rate of fuel consumption and substantially increases the weight carried by the vessel. As a result, it would be highly beneficial to provide an outboard propulsion system which can substantially increase the drive potential of an engine without causing a corresponding increase in fuel consumption and without necessitating the added weight of a second motor on the vessel.
In the past, there have been dual propeller assemblies, such as those recited in the patents to W. C. Conover, U.S. Pat. No. 2,672,115, and Brandt, U.S. Pat. No. 4,529,387, which have utilized two propellers to increase the drive potential of the motor. These assemblies, however, utilize two propellers mounted in line with one another on the same propulsion shaft, thereby acting more like a single larger propeller than a pair of spaced, independent propeller assemblies which are disposed to function much like two separate outboards mounted in spaced apart relation from one another on the marine vessel. Further, propeller drives such as the one recited in the patent to Billing, U.S. Pat. No. 2,372,247, while separating the propellers are directed towards minimizing hydraulic torque and not to increasing the drive potential of the motor. The present invention specifically provides a pair of spaced independent propeller assemblies which function together to increase the drive potential of a single motor having a single drive shaft. Also, by providing a large drive gear to small secondary gear ratio, the power output in terms of revolutions per minute is effectively increased to further maximize the drive potential of the assembly.